For casual wear, pick the recommended size. To use this as an insulating layer with a closer fit, pick the recommended size, or even better, one size smaller. The knit stretches a lot and by avoiding a loose fit, you won't bunch the garment.

The dude in most pictures is 175 cm (5' 9") tall with a 100 cm (39.5") chest. He was the happiest with Small. He also wears Medium in a comparison photo.

The upper end of the recommended user height is also flexible.

Here are the actual measurements of the overalls themselves, please note that the knit is very stretchy!

The sleeve length in every size is 27.5".

Metric

Imperial

Care

Machine wash with a wool program and use a wool detergent. Wool detergents retain wool's natural resistance to dirt and odors. However, you rarely need to wash wool—just air it out, and that'll usually do the trick.

The terry knit is fairly smooth on the outside and has loops on the inside to trap air and insulate better. The loops have limited tightness, so avoid using hook-and-loop stuff and other rough items against the jacket.

Wool also pills a bit, especially where your arms meet the sides. Pilling can be removed gently with a buzzing machine or carefully with a razor blade; just avoid damaging the thread of the knit itself.